Fuse plug



A ril 20, 1926. 1,581,637

O. H. JUNG FUSE PLUG Filed May 14, 1925 Oscar H Jung Patented Apr. 20, 1926.

F F EQE.

OSCAR H. JUNG, 0F MILWAUKEE, WISCONSIN.

FUSE PLUG.

Application fled May 14, 1925. Serial No. 80,286.

To all whom it may concern:

Be it known that I, OSCAR H. citizen of the United States, and resident of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Fuse Plugs;

and I do hereby declare that the following is a full, clear, and exact description thereof.

This invention relates to fuse plugs. Objects of this invention are to provide a fuse plug in which there is no possibility of an arc forming between the center pin and the outer screw shell irrespective of the initial are formed during the rupture of the fuse, in which a perfect battle is provided between the center pin and the outer shell, in which evenly positioned openings are provided adjacent the transparent window of the fuse plug,,and in which a passage is provided for the gases along a tortuous or cir'-' cuituous route through mutilated threads formed between the body of the fuse plug and the outer screw shell.

Further objects are to provide a fuse plug of such construction that the transparent window is bowed inwardly to resist the internal pressure, thus permitting the use of a very thin mica or similar material, and in which all of the gases are directed towards the window to insure a complete blacking of the window when the fuse blows.

Further objects are to provide a fuse plug which is of simple construction, and in which the parts may be easily assembled.

An embodiment of the invention is shown in the accompanying drawings, in which Figure 1 is a longitudinal section through the plug.

Figure 2 is a view of the plug detached.

Figure 3 is a view of the thimble or inner portion detached.

Figure 4 is a. bottom view of the plug. Figure 5 is a sectional view taken on line 5-5 of Figure 1. I

Referrin tothe drawings, it will be seen that the bod portion comprises an outer end or head 1 w ich is preferably knurled to facilitate screwing of the fplug into the socket. This body portion is o insulating material such as porcelain, and has a rearwardly exthe body portion of .the

- tending cylindrical portion 2 which is provided with threads 3. These threads are mutilated to provide gaps 4 at-numerous points for a pur ose hereinafter to appear. Further, it wi I be noted that the shell 2 JUN(;, a-

of the body portion is provided with a .pair 2f diametrically opposed rectangular notches The thimble or inner bathe member comprises a shell or cylindrical portion 6 (see F lgures 1 and 3) which is of lesser diameter than the internal diameter of the shell 2 of the body portion. s provided with a plurality of notches 7 at its upperend, one of which 7 it is to be noted is larger than the remaining notches and receives the fusible element.

It is to be noted per or outer end 0 the thimble 6 or inner shell and the adjacent portion of the body part of the fuse are curved so that a mica w1ndoW 8 positioned therein will be bowed inwardly, as shown in Figure 1, and will be held in this bowed position when the plug is fully assembled. letting-material and is provided with a flange 9 at its outer end and with a pair of rectangular lugs 10 adapted to seat in the notches 5 of the body portion. It is provided furtherwith a tapered rear portion 11 which is apertured to receive the central electrical contact 12 as shown in Figure 1. This central electr cal contact is provided with a pair of wings or arms 13 which are pressed outwardly, as shown in Figure 1, to engage the beveled inner surface of the thimble 6 and to thus firmly retain the central electrical contact in position.

. An outer metallic shell orthreaded ferrule 14 is'screwed upon the threads 3 of the body portion. It is to be noted that this ferrule is provided with an inwardly folded rear flange 15. Preferably, this flange is crlmped at 15 into the spaces 16 (see Figure 4) formed rearwardly of the lugs 10 1n the thimble 6 (see Figure 3).. Thus, after the flange is in position, it is'securely locked against rotation.

The fusible element comprises a strip 17 of easily fusiblematerial which is attached to the central electrical contact by means of a drop of solder 18 positioned between the This cylindrical member The thimble 6 is of insu-- arms 13 of such central electrical contact.

This drop of solder further reenforces the arms 13 and prevents their inward folding. The fusible element extends outwardly in a slanting manner, shown in wards the member 8, and extends transversely adjacent such window. It is provided Figure 1, to-

with a restricted portion 19 adjacent. the

window So as to insure its opening at this between said thimble and body ortion to said metal ferrule, whereby a ba e is provided and the blackening of the mica window is assured upon blowing of the fuse.

4. A fuse plug comprising a body having a rearwardly extending cylindrical provided with mutilated threads on its outer side, a thimble having a cylindrical portion positioned with said body portion and spaced therefrom, a center electrical contact carried by said thimble, a threaded metal ferrule screwed upon the mutilated threads of said body portion and providing therebetween portion atortuous passage, and holding said thimble in place, said thimble having notches at the end of its cylindrical portion into which a portion of said metal ferrule is crimped, and a fusible element extending from said center electrical contact, through said thimble, and between said thimble and body portion to said metal ferrule.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in' the county of Milwaukee and State of Wisconsin.

OSCAR H. JUNG. 

